In recent years, the use of medical image diagnosis apparatus has increased with the progress of computer technology. As a result, there has also been a large increase in the need for hard copies for diagnostic records. Thus, imagers having a higher speed and a smaller size have been desired. However, even if a laser imager integrated with an automatic processor attains a high exposure speed, there is a waiting period if the photographic material cannot be processed rapidly in the automatic processor. Thus, it would be advantageous to adapt the photographic material to rapid processing. Previously if the automatic development is effected at a high speed, there have been problems in that strong residual color takes place due to elution of the photographic material with the processing solutions. It has also been disadvantageous in that decomposition of the photographic material takes place by the change in the hydrogen ion concentration or completion of the processing without sufficient progress of various reactions of antihalation dyes which have been reduced and decolored by sulfurous ions in the development, fixing and washing procedures in the automatic processor.
Further, these reactions can also take place as the temperature of the washing water becomes higher. Thus, the level of residual color may change with different temperatures of washing water, although this problem is often not recognized as being caused by uneven residual color. Hospitals in Japan often encounter the circumstances in which the temperature of washing water ranges from 5.degree. to 6 .degree. C. in winter time to over 30.degree. C. in summer time. However, practitioners of medical image technology often encounter the situation in which a current image is compared with records obtained several months ago to observe a change with time. Thus, the change in the image color from season to season is undesirable. In order to cope with these difficulties, the temperature of washing water must be kept constant. However, this approach is impractical since it causes a rise in energy loss and requires a space for the installation of an apparatus for keeping the temperature of washing water constant.
In order to accelerate these reactions, a water-soluble group, such as sulfonic group and carboxylic group, may be introduced into the dyes as disclosed in JP-A-62-123454 (the term "JP-A" as used herein means an "unexamined published Japanese patent application").
However, since the increase in the processing speed is remarkable particularly in the field of photographic material for laser light, these approaches are limited. Further, the number of antihalation dyes which can be selected for this purpose are limited as well.
Moreover, antihalation dyes which have been decolored are again colored due to side reactions, such as oxidation. As a result, these antihalation dyes color the washing water or contaminate the roller in the automatic processor. In addition, antihalation dyes which have been concentrated (colored again) from the washing water by drying air on a squeeze roller may be then transferred to the photographic material being processed.
The above-stated trouble due to use of the antihalation dyes which have been colored again often takes place as the replenishment rate of the developer or fixing solution is decreased, making it difficult to reduce the amount of waste developer or fixing solution.